When we retrospect the field of history in the vast stretch of
time from the beginning of Christianity to our own day, the
various heresies that have from time to time appeared, seem
clearly and distinctly marked off from the environment of the
orthodox faith. We seem to be able to (46) draw a geometrical
line around about their respective areas, sharply dividing the
camp of truth from that of error, separating the light from the
darkness. But in this we are deceived; it is an illusion caused
by distance. The distinction appears so clear, so definite only
because we stand on the eminence of the present, from whose
vantage ground we see, in large outline, the massed movements of
peoples in the vast panorama of the past. A closer study, placing
us in intellectual contact with these epochs, enables us to
observe that never, in any period of history, were the dividing
lines between truth and error defined with such geometrical
exactness; not that truth in reality was not clearly and
distinctly formulated in the definitions of the Church, but
because in its acceptation and its exterior profession by the
generations interested in these definitions, more or less
confusion and looseness characterized their manner of taking
them.

Error in society is like a stain upon some precious tissue. It
is easily distinguished, but it is very difficult to define its
limits. These limits are as indefinite as the twilight which
merges the departing day into the coming night or the dawn which
blends the shadows of the spent darkness with the newborn light.
So do the limits between (47) error and truth in the actual
affairs of men mingle in shadowy confusion. Error is a somber
night; its limits fringe away from it like a huge penumbra, which
is sometimes taken for the shadow itself, faintly brightened by
some reflections of the dying light, or rather by the luminary
yet enveloped and obscured by the first shades of evening.

So all error clearly formulated in Christian society is, as it
were, surrounded by an atmosphere of the same error, but less
dense, more rarefied and tempered. Arianism had its SemiArianism,
Pelagianism its SemiPelagianism, Lutheranism has its
SemiLutheranism, which is nothing else than Catholic Liberalism.
This is what the Syllabus terms modern Liberalism, that is,
Liberalism without the boldness of its unvarnished first
principles and stripped of the horrors of its last consequences;
it is the Liberalism of those who are still unwilling not to
appear to be Catholics or at least not to believe themselves
Catholics. Liberalism is the baneful twilight of the truth
beginning to be obscured in their intelligence, or heresy which
has not yet taken complete possession.

On the other hand we should not fail to (48) note that there
are those who are just emerging from the darkness of error into
the twilight of truth. This class has not fully penetrated into
the domain of truth. That they will ever enter the city of light
depends upon their own sincerity and honesty. If they earnestly
desire to know the truth in its fullness and seek it with sincere
purpose, God's grace will not fail them. But they are in a
dangerous position. On the border land between the realms of
light and darkness the Devil is most active and ingenious in
detaining those who seem about to escape his snares, and spares
nothing to retain in his service a great number of people who
would truly detest his infernal machinations if they only
perceived them. His method in the instance of persons infected
with Liberalism is to suffer them to place one foot within the
domain of truth provided they keep the other inside the camp of
error. In this way they stand the victim of the Devil's deceit
and their own folly. In this way those whose consciences are not
yet entirely hardened, escape the salutary horrors of remorse; so
the pusillanimous and the vacillating, who comprise the greater
number of Liberals, avoid compromising themselves by pronouncing
themselves openly and squarely; so the shrewd, calculating
according to the measure of (49) expediency how much time they
will spend in each camp, manage to show themselves the friends
and allies of both; so a man is enabled to administer an official
and recognized palliative to his failings, his weaknesses, and
his blunders. It is the obscurity that rises from the
indefiniteness of clearly defined principles of truth and error
in the Liberalist's mind that makes him the easy victim of Satan.
His boasted strength is the very source of his weakness. It is
because he has no real solid knowledge of the principles of truth
and error that he is so easily deluded into the belief of his own
intellectual superiority. He and pride, cunningly played upon by
Satan, are invariably drawing him.